Conspiracy Theories require persons easily deceived. Persons who have a sense of powerlessness, a belief that there are unknown powers out there which manipulate them.
Due to fear they are willing to believe certain things do not really exist.. It is easier for a limited intellect to claim Corvid 19 is a ‘Cornyflu’ than to appreciate the world is in the grip of a pandemic.
Because of their uncontrollable fear, those who spread the Conspiracy Theories feel more in control when they find a group they can blame.
Their hatred and prejudice are just below the surface. They hate everyone who isn’t like them; race, religion, political persuasion.
This is because, being weak, they need to blame other people for their failings.
There are many people like this all through history. They blamed the Bubonic Plague on these people, Spanish flu on those people, etc.
This is because they need to blame someone for what they can’t control.